Looks like it's a FM transmitter , the capacitor on the collector just decouples the antenna (the arrow pointing up) from the tank.

The audio input goes in the bottom (at the circle) , coupled with a big capacitor, from a low impedance dynamic microphone, this modulates the base emitter voltage, hence modulates the base emitter capacitance and shifts the frequency, (you also get a bit of AM) .

Or it could be something completely different......Its hard to second guess someone else's design.

Actually, the fact that we are discussing this in the first place indicates that there probably is a systemic problem the EE fields have in general. I have been telling *every* kid that I have seen to take up a trade, no matter what it is, because the job market for STEM degrees can not be trusted. While globalization might be inevitable, the rampant age discrimination means that your career is over at the age of 40 - no matter what the tech field is. Top that with companies that *work hard* to cheat on H1B visas just so they can save dimes on employees also tells potential career engineers that they are not seen as a resource or woth an investment, but rather as a cost that that needs to be reduced or cut outright. Plus, why hire an employee who wants vacation days when you can buy that fancy new tool to get the job done for you?

STEM is a dead end kids. Become a plumber. That's where it is at. Really.

@Max : Sadly back then photos where on neagtive and paper, and the Research Lab never let me touch a Hasalblad again, after dropping one from the top of a double decker bus. So not much remains. When the lab closed down to outsourcing, all the lab built equipment got dumped in a tip and I was in a different section of the company so never new my creations were in the tip.

Our electronic circuit diagrams drawn on squared paper got shredded.

So much easier today to take a quick picture and save your drawings on a computer and keep all of it on your own cloud server.

However ther are advantages and disavantages to this. Once in the open domain can anyting truly be said to be erased?

I'm a jumped up electronic designer that started as a Electronics Tech. I understand RF, Power, And Analog logic. I red lined and corrected so many schematics on specials and new designs I ended up in a Engineering cube when the Old Analog guy retired. I'm the PCB layout and analog guy here. My skills are many and varied due to my USAF training and career. I understand everything from aerodynamics to RADAR, GPS, IFF, instrumentation, leadership and teamwork. I worked on systems with time shared wiring and high power. I am still under security restrictions and I retired From the AF nearly 20 years ago.

YET, I still have trouble finding a new position with decent pay for one reason. I have a pile of college credits but not enough at any one place to get even a 2 year degree. I Retired one credit short of my degree at CCAF from the did a recount on the last day. And NO-ONE will accept half of those credits, yet they were learned the hard way, On the Job with actual classes periodically.

And since I'm in my late 50's I can't afford the TOI of getting a degree now.

But to the article. I'm the analog guy here. We have another guy that was hired right from college and he does the digital stuff. Then I interface it with the real world. We design and sell sensing, measurement, instrumentation, and closed loop control systems for moving web processes.

To do that We measure minute forces in analog, convert to digital, calibrate, process and output back to analog machines (drives, clutches and brakes). So we do A-D and D-A on every unit. I understand the problem of high speed digital polluting my analog sensing and we must avoid it diligently. A former Manager here told people I do things so far outside the box that he didn't think I'd ever seen it. Probably because in the view from academia, I haven't.

But how do I convert that to something an HR person can do buzzword bingo on and get a job?

THAT is the problem these companies have. We are out there, but they don't see us because they don't speak the language of complex system interactivity and all they know is a list of acronyms that do not mean anything to them.